This invention relates to termination posts as used in printed circuit boards and more particularly, relates to those termination posts which may be electrically insulated and, therefore, isolated from the printed circuit board.
While this invention has broad application to termination posts in general, the remainder of the discussion in this specification will be limited to wire wrap posts, a specific type of termination post. However, this limitation is for ease and clarity of discussion only. Whenever in this specification the term "wire wrap post" is used, it should be understood that termination posts in general are also contemplated within the scope of the invention.
Wire wrap posts are an integral part of the circuitry of printed circuit boards, as is well known to those skilled in the art. These wire wrap posts are typically inserted in the "plated-through" holes of the printed circuit boards.
At times, it may be desirable to electrically insulate the wire wrap post so as to isolate it from the plated-through hole. For example, if there is a mistake in the design of the printed circuit board, it would be advantageous to isolate the mistake by isolating the wire wrap post rather than design a new printed circuit board. Another example is the isolating of particular wire wrap posts so as to install design improvements to existing pieces of equipment rather than again, designing a new printed circuit board. In general, it would be desirable to modify the printed board circuit without redesigning the circuit board. This may be accomplished by electrically insulating the wire wrap post to form a circuit change pin.
The current technique for electrically insulating the wire wrap post is to form the bottom part of the wire wrap post into a generally C-shaped, cross-sectional configuration and then coating this part of the wire wrap post, that is, the part that engages the plated-through hole, with an insulating coating. The C-shaped, cross-sectional configuration gives the wire wrap post a certain transverse springiness, which retains the wire wrap post in the plated-through hole. However, the deflection of the C-shaped, cross-sectional configuration is such that the amount of irregularity in the plated-through hole that can be accommodated is limited.
While this prior art insulated wire wrap post has worked generally satisfactorily, it would be desirable to have an improved design. Accordingly, it is an object of this invention to have an improved circuit change pin.
It is another object of the invention to have a circuit change pin that is simple in design and effective in use.
These and other objects of the invention will become apparent after reference to the following description considered in conjunction with the accompanying drawings.